Year 9 Science – Forces 1
Practise finding net force, predicting motion, two-step weight calculations, electrostatics, orbits, magnet and electromagnet investigations, and mechanical advantage. 20 questions. 25 minutes.
Three horizontal forces act on a box. What is the net force on the box?
Choose the word or number that completes each blank.
A parachutist weighing 800 N falls at a steady speed. The air resistance on her is 1, so the net force on her is 2.
Blank 1: less than her weight · greater than her weight · equal to her weight
Blank 2: upward · zero · downward
Circle 2 words in the sentence below.
A bike skids to a stop. Click the two kinds of energy that friction changes the bike's kinetic energy into.
magneticheatelectricalsoundchemical
What will the trolley do next?
Choose the word that completes each blank.
Astronauts in the space station seem to float because gravity on them is 1, and they are in continual 2 around Earth.
Blank 1: still acting · zero · cancelled by the station
Blank 2: free fall · balanced motion · rest
A plastic ruler becomes negatively charged when it is rubbed with a cloth. What happened during rubbing?
Choose the word that completes each blank.
When a balloon is rubbed on hair, 1 move from one object to the other, and the balloon and hair end up with 2 charges.
Blank 1: protons · whole atoms · electrons
Blank 2: like · opposite · no
A worker pushes a trolley with a steady 40 N force and 120 J of energy is transferred to it. How far was the trolley pushed?
A 20 kg backpack is carried from Earth (g = 10 N/kg) to the Moon (g = 1.6 N/kg). Choose the answer for each blank.
On Earth the backpack weighs 1 and on the Moon it weighs 2.
Blank 1: 2 N · 20 N · 200 N
Blank 2: 32 N · 12.5 N · 320 N
Circle 1 word in the sentence below.
A sled at rest is pulled by three forces: 50 N to the right, 20 N to the left and 30 N to the left. Click the word that describes what the sled does.
acceleratesdeceleratesstationaryreverses
A space probe weighs 300 N on Earth (g = 10 N/kg). On the Moon g = 1.6 N/kg. What does the probe weigh on the Moon?
Choose the word that completes each blank.
Iron filings around a bar magnet bunch most thickly at the 1, showing the magnetic field is 2 there.
Blank 1: middle · poles · sides
Blank 2: weakest · strongest · reversed
A pulley system lets a worker lift a 600 N load using an effort of 150 N. What is its mechanical advantage?
A student tested how distance affects a magnet's pull. Which change would make the results more reliable?
| Distance (cm) | Paperclips held |
|---|---|
| 1 | 12 |
| 2 | 7 |
| 4 | 3 |
| 8 | 0 |
Two ramps rise to equal heights and friction is ignored. Ramp A is 2 m long and ramp B is 4 m long. Choose the word that completes each blank.
Pushing a trolley up ramp B needs 1 force than ramp A, and the energy transferred to the trolley is 2.
Blank 1: less · the same · more
Blank 2: less · more · the same
A satellite is orbiting Earth when Earth's gravity on it stops completely. What does the satellite do next?
Circle 2 words in the sentence below.
A student tests how the number of turns affects an electromagnet's strength. Click the two variables that must be kept constant.
turnscellsclipscore
On a different planet, a 6 kg rock weighs 90 N. What is g on that planet?
A student concludes that doubling the turns more than doubled the electromagnet's strength. Why is this conclusion not valid?
A lever balances with a 200 N load 0.3 m from the pivot. The effort is applied 1.2 m from the pivot on the other side. What effort is needed?